1. Field of the Invention
This invention relates to an apparatus for recording and reproducing a video signal on and from a magnetic tape.
2. Description of the Related Art
Some video tape recorders (VTR""s) are based on a standard format referred to as a VHS format. There is an S-VHS format which improves over the VHS format. A VTR of the S-VHS standard can record and reproduce a video signal which is wider in frequency band and higher in picture quality than a video signal handled by a VTR of the VHS standard.
The VTR of the S-VHS standard uses an exclusive magnetic tape referred to as an S-VHS tape. The S-VHS tape is designed to more suit with a video signal having a wide frequency band and short wavelengths in comparison with a VHS tape.
In the VTR of the VHS standard, a video signal to be recorded is separated into luminance and chrominance signals. The luminance signal is converted or modulated into an FM modulated luminance signal having a frequency deviation of 3.4 to 4.4 MHz.
The chrominance signals are down-converted into a low frequency band around 629 kHz. The FM modulated luminance signal and the frequency-down-converted chrominance signals are combined before being recorded on a VHS tape.
In the VTR of the S-VHS standard, a video signal to be recorded is separated into luminance and chrominance signals. The luminance signal is converted into an FM modulated luminance signal having a frequency deviation of 5.4 to 7.0 MHz. The chrominance signals are down-converted into a low frequency band around 629 kHz. The FM modulated luminance signal and the frequency-down-converted chrominance signals are combined before being recorded on an S-VHS tape.
The VTR of the VHS standard can use an S-VHS tape instead of a VHS tape. In general, the VTR of the S-VHS standard can operate in each of two different modes, a VHS mode and an S-VHS mode. During the VHS mode of operation of the S-VHS VTR, a video signal of the VHS format is recorded on a VHS tape or an S-VHS tape. During the S-VHS mode of operation of the S-VHS VTR, a video signal of the S-VHS format is recorded on an S-VHS tape.
In general, an S-VHS tape is contained in a cassette having an identification hole which indicates that the tape therein is of the S-VHS type. The VTR of the S-VHS standard has a function of sensing an identification hole in a tape cassette placed therein. When the S-VHS VTR senses an identification hole in a tape cassette, the S-VHS mode of operation is automatically started. On the other hand, when the S-VHS VTR fails to sense an identification hole in a tape cassette, the VHS mode of operation is started.
An advanced VTR detects characteristics of a used magnetic tape, and records a video signal on the magnetic tape under recording conditions (that is, the VHS mode or the S-VHS mode) determined in response to the detected tape characteristics. The advanced VTR can optimize signal recording tape by tape.
Specifically, the advanced VTR implements a preliminary process before the recording of a video signal. During the preliminary process, the advanced VTR records and reproduces a test signal on and from a used magnetic tape. The advanced VTR detects characteristics of the magnetic tape (that is, the VHS tape or the S-VHS tape) from the reproduced test signal. Then, the advanced VTR records a video signal on the magnetic tape under recording conditions determined in response to the detected tape (the VHS tape or the S-VHS tape) characteristics.
As previously explained, the S-VHS VTR operates in the VHS mode when a VHS tape is used. Some VHS tapes have improved characteristics sufficient to store wide-band and high-quality video signals. In general, S-VHS tapes are higher in price than VHS tapes.
It is an object of this invention to provide a magnetic recording and reproducing apparatus which can record and reproduce a wide-band and high-quality video signal on and from an inexpensive magnetic tape such as a VHS tape.
A first aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for recording a video signal of a high-quality format, which has a first given frequency band, on a standard magnetic tape designed to record a video signal of a standard format having a second given frequency band narrower than the first given frequency band; and second means for reproducing a video signal of the high-quality format from a standard magnetic tape.
A second aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for recording a video signal of a first standard format, which has a first given frequency band, on a magnetic tape of a first standard type designed to record a video signal of the first standard format;
second means for recording a video signal of a second standard format, which has a second given frequency band wider than the first given frequency band, on a magnetic tape of a second standard type designed to record a video signal of the second standard format; third means for recording a video signal of a high-quality format, which has a third frequency band wider than the first frequency band, on a magnetic tape of the first standard type; fourth means for reproducing a video signal of the first standard format from a magnetic tape of the first standard type; fifth means for reproducing a video signal of the second standard format from a magnetic tape of the second standard type; and sixth means for reproducing a video signal of the high-quality format from a magnetic tape of the first standard type.
A third aspect of this invention is based on the first aspect thereof, and provides a magnetic recording and reproducing apparatus further comprising third means for detecting whether or not the video signal reproduced by the second means is of the high-quality format.
A fourth aspect of this invention is based on the third aspect thereof, and provides a magnetic recording and reproducing apparatus further comprising fourth means for detecting whether a tape-type identification hole is present in or absent from a housing of the standard magnetic tape accessed by the second means; fifth means for detecting a frequency band of the video signal reproduced by the second means; and sixth means for detecting whether or not the video signal reproduced by the second means is of the high-quality format in response to a result of the detection by the fourth means and the frequency band detected by the fifth means.
A fifth aspect of this invention is based on the third aspect thereof, and provides a magnetic recording and reproducing apparatus further comprising a reproducing FM equalizer for processing the video signal reproduced by the second means; a de-emphasis circuit for processing the video signal reproduced by the second means; a noise canceller for processing the video signal reproduced by the second means; and fourth means for controlling a signal processing characteristic of at least one of the reproducing FM equalizer, the de-emphasis circuit, and the noise canceller in response to a result of the detection by the third means.
A sixth aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for processing an input video signal into a processing-resultant video signal having a first given frequency band; second means for recording the processing-resultant video signal, which is generated by the first means, on a standard magnetic tape designed to record a standard-format video signal having a second given frequency band narrower than the first given frequency band; third means for reproducing a video signal having the first given frequency band from a standard magnetic tape; and fourth means for recovering an original video signal from the video signal reproduced by the third means.
A seventh aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for processing an input video signal into one among a video signal of a first standard format having a first given frequency band, a video signal of a second standard format having a second given frequency band wider than the first given frequency band, and a video signal of a high-quality format having a third given frequency band wider than the first given frequency band; second means for recording the video signal of the first standard format, which is generated by the first means, on a magnetic tape of a first standard type designed to record a video signal of the first standard format; third means for recording the video signal of the second standard format, which is generated by the first means, on a magnetic tape of a second standard type designed to record a video signal of the second standard format; fourth means for recording the video signal of the high-quality format, which is generated by the first means, on a magnetic tape of the first standard type; fifth means for reproducing a video signal from a magnetic tape; sixth means for detecting whether the video signal reproduced by the fifth means is of the first standard format, the second standard format, or the high-quality format; and seventh means for processing the video signal reproduced by the fifth means into an original video signal in response to a result of the detection by the sixth means.
An eighth aspect of this invention provides a magnetic recording and reproducing apparatus comprising first means for detecting whether a magnetic tape is of a first standard type, a second standard type, or a third standard type, the first standard type being designed to record a video signal of a first standard format having a first given frequency band, the second standard type being designed to record a video signal of the first standard format and being capable of recording a video signal having a frequency band wider than the first given frequency band, the third standard type being designed to record a video signal of a second standard format having a second given frequency band wider than the first given frequency band; second means for processing an input video signal into a video signal of the first standard format when the first means detects that the magnetic tape is of the first standard type, for processing the input video signal into a video signal of a high-quality format having a third given frequency band wider than the first given frequency band when the first means detects that the magnetic tape is of the second standard type, and for processing the input video signal into a video signal of the second standard format when the first means detects that the magnetic tape is of the third standard type; third means for recording the video signal generated by the second means on the magnetic tape; fourth means for reproducing a video signal from a magnetic tape; fifth means for detecting whether the video signal reproduced by the fourth means is of the first standard format, the second standard format, or the high-quality format; and sixth means for processing the video signal reproduced by the fifth means into an original video signal in response to a result of the detection by the fifth means.
A ninth aspect of this invention provides a video signal processing apparatus comprising a first video signal processing circuit; and a second video signal processing circuit connectable to the first video signal processing circuit; wherein the first video signal processing circuit and the second video signal processing circuit comprise means for processing either a video signal of a standard format or a video signal of a high-quality format into a record signal in the presence of the second video signal processing circuit connected to the first video signal processing circuit, and the video signal of the high-quality format is higher in picture quality than the video signal of the standard format and is wider in frequency band than the video signal of the standard format ; and wherein the first video signal processing circuit comprises means for processing a video signal of the standard format into a record signal in the absence of the second video signal processing circuit.
A tenth aspect of this invention is based on the ninth aspect thereof, and provides a video signal processing apparatus wherein in the presence of the second video signal processing circuit connected to the first video signal processing circuit, the first video signal processing circuit and the second video signal processing circuit are in a magnetic recording apparatus for a video signal of the high-quality format, and wherein in the absence of the second video signal processing circuit, the first video signal processing circuit is in a magnetic recording apparatus for a video signal of the standard format.
An eleventh aspect of this invention provides a video signal processing apparatus comprising a first video signal processing circuit; and a second video signal processing circuit connectable to the first video signal processing circuit; wherein the first video signal processing circuit and the second video signal processing circuit comprise means for processing either a reproduced video signal of a standard format or a reproduced video signal of a high-quality format into an original video signal in the presence of the second video signal processing circuit connected to the first video signal processing circuit, and the reproduced video signal of the high-quality format is higher in picture quality than the reproduced video signal of the standard format and is wider in frequency band than the reproduced video signal of the standard format; and wherein the first video signal processing circuit comprises means for processing a reproduced video signal of the standard format into an original video signal in the absence of the second video signal processing circuit.
A twelfth aspect of this invention is based on the eleventh aspect thereof, and provides a video signal processing apparatus wherein in the presence of the second video signal processing circuit connected to the first video signal processing circuit, the first video signal processing circuit and the second video signal processing circuit are in a magnetic reproducing apparatus for a video signal of the high-quality format, and wherein in the absence of the second video signal processing circuit, the first video signal processing circuit is in a magnetic reproducing apparatus for a video signal of the standard format.